The present invention relates to a failure estimation apparatus and a failure estimation method. More specifically, the invention is favorably applicable to a failure estimation apparatus and a failure estimation method for an apparatus that includes a semiconductor power device.
Recently, the trend of IoT (Internet to Things) is increasing in the field of FA (Factory Automation). For productivity improvement, a FA instrument is networked to manage operating conditions of the instrument such as an operation late and the life. A factory manager (end user) adjusts the replacement availability in the event of a failure or estimates the maintenance time based on information collected from the FA instrument.
The FA instrument uses a power module for motor driving that includes a power semiconductor device (power device). A failure in parts including the power device often causes a serious effect. To avoid this, life estimation is performed to replace parts before an actual failure occurs. It is important to estimate the time to replace a part when the part fails after it is used until failed.
Patent literature 1 discloses a power cycle life estimation method for an IGBT module that includes an insulated gate bipolar transistor (IGBT) as a power device. The method computes the module life by comparing a power cycle life curve resulting from a previously conducted power cycle test with an actual measurement value using a temperature sensor included in the IGBT module. The power cycle test generates a heat stress that increases and decreases the IGBT bonding temperature in a relatively short time. The power cycle test observes characteristics changes until destruction and acquires a power cycle life curve. Patent literature 1 focuses on the fact that the power cycle life curve is formed by several lines with different gradients and includes an inflection point. The life estimation is performed based on the inflection point. This improves the estimation accuracy.
Patent literature 2 discloses a remote vehicle failure estimation system. A failure estimation server previously acquires vehicle data before failure occurrence from a failed vehicle via the network. The failure estimation server relates the acquired vehicle data to vehicle data collected from a failure-estimated vehicle and determines whether or not the failure-estimated vehicle may fail in the near future. Specifically, the server performs correlation operation on vehicle data before failure occurrence acquired from a failed vehicle and vehicle data received from a failure-estimated vehicle. If some degree of correlation is identified in both vehicle data, the server estimates that a failure similar to the failed vehicle occurs. The server notifies the estimation result to a customer of the failure-estimated vehicle and calls his or her attention.    Patent literature 1: Japanese Unexamined Patent Application Publication No. 2011-196703    Patent literature 2: Japanese Unexamined Patent Application Publication No. 2004-268633